Anonymous claims to have hacked the US Justice Department website and posted 1.7 gigabytes of data on The Pirate Bay file-sharing site.

The department acknowledged that its server has been breached. The attack was part of the Operation Monday Mail Mayhem, a new campaign set up by Anonymous to protest against corruption in the US government.

"Today we are releasing 1.7GB of data that used to belong to the United States Bureau of Justice, until now," reads a statement posted on The Pirate Bay. "Within the booty you may find lots of shiny things such as internal emails, and the entire database dump."

The collective also reported that the Justice Department tried to shut down its statistics website to prevent the attack, but it was already too late.

A spokesperson for the Justice Department admitted that users gained access to a server operating the department's Bureau of Justice Statistics website, Reuters reported, and that it was investigating the accident.